Why I like it
kubectl exec -it shell-demo -- /bin/bash
kubectl apply is up there but this guy lets you run a bash terminal on a running pod. This is great for investigating local files or anything else you didn't think of preparing for originally within the container.
https://kubernetes.io/docs/tasks/debug-application-cluster/get-shell-running-container/
Shout out to https://www.jeffgeerling.com/blog/2018/updating-kubernetes-deployment-and-waiting-it-roll-out-shell-script for an excellent replacement for kubectl wait.